1. Field of the Invention
The instant disclosure relates to a compensation circuit; in particular, to a compensation circuit that can adjust the response time, and an energy storage device using the same.
2. Description of Related Art
With the development of technology, the portable electric device has become an essential tool in our lives, such as mobile phones, tablets, music players or video players having a USB transmission interface.
The power is consumed quickly for the portable electric device, so the user would usually have an energy storage device, such as a power bank, to charge the portable energy storage device. The energy storage devices generally have the OTG (On the Go) function. In other words, the energy storage device can be viewed as a peripheral equipment that receives energy from other devices, such as a computer. The energy storage device can also be a host device to charge the slave electric devices. In addition, recently, an energy storage device has come up, which can be charged by the outside electric energy and can charge the slave electric devices simultaneously.
Usually, there would be a detection circuit and a compensation circuit in an energy storage device. The compensation circuit comprises a plurality of amplifiers, comparators, resistors and capacitors. The detection circuit comprises a plurality of sensing loops to detect the voltage and the current of the energy storage device. For example, the detection circuit can detect the input voltage and the input current generated by the outside electric energy, or the output voltage and the output current provided by the battery of the energy storage device. The compensation circuit is configured to provide the compensation to each sensing loop to respond with the load needed by the portable electric device.
However, in the traditional compensation circuit, the resistance and the capacitance are both fixed, so the compensation circuit can only provide one compensation value. In other words, the response time of each sensing loop responding to the load change of the electric device is constant, wherein the response time refers to the time from the timing when the load of the portable electric device changes to the timing when the energy storage device correspondingly starts to support energy. Thus, the traditional compensation circuit cannot provide different compensation values with respect to the detecting result of each sensing loop, and the response time of the energy storage device cannot be shortened.